


A

by AssortedHeroes



Series: Death's Child [1]
Category: Death Note & Related Fandoms, Percy Jackson and the Olympians - Rick Riordan
Genre: Angst, Canonical Character Death, Eventual Romance, Flashbacks, Geniuses, Hades is a Good Parent, Loss of Parent(s), Mind Games, Moral Ambiguity, Multi, Prophetic Dreams, Quests, Rebellion, Talking To Dead People, Teenage Rebellion?, Titan War
Language: English
Status: In-Progress
Published: 2018-01-22
Updated: 2018-01-24
Packaged: 2019-03-08 06:59:55
Rating: Not Rated
Warnings: Major Character Death
Chapters: 2
Words: 2,835
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/13452924
Author URL: https://archiveofourown.org/users/AssortedHeroes/pseuds/AssortedHeroes
Summary: There was never a time when she was unsure of herself.That was before her father gave her a death quest.-After a young teenaged girl appears in the Yagami household, claiming to have information on Kira, the great detective L reluctantly allows her to work with him on this investigation. The supernatural is her forté, after all, and despite her youth she happens to be an extremely intelligent young woman - what else would you expect for his half-sister? Join the cast of Death Note as they discover what exactly is going on with the help of a demigod daughter of Hades.Alternately: Light has no idea where this girl came from and how she knows things and it scares him, L is worried for his baby sister who shouldn't be here, Hades has trouble with his teenaged children, and Mello really should find this Greek business more alarming.(Title is a placeholder. Maybe.)[Written by K.]





	1. First Meeting

**Author's Note:**

> Hoo boy. Howdy. This might be a confusing story for those who don't know much of the lore around Percy Jackson, so if you're interested in this, I'd advise you to brush up a little on your Greek Mythology and stuff. Not so much with Death Note, though, so don't worry. For the sake of the story, we're following anime timeline here, and the idea that the Great Prophecy takes place in 2013. Not many real changes have been made to either verse so I wouldn't worry about that, either. All I really have to say beyond that is that POV will rarely focus on our heroine directly and will more often be a character speaking to her instead.
> 
> Enjoy!

Light Yagami, the brilliant seventeen-year-old whose test scores far outpaced the rest of Japan’s and the boy who always knew what to say, stared at the girl standing across the street from him and could only blink, dumbfounded.

He had been walking home from school with a fresh list of criminals in mind as usual and had just entered a resitential area when he’d spotted her (not that she was hard to miss) plucking her way through a throng of giggling girls with some vacant expression. She’d looked directly at Light with dull black eyes and smiled, and then, her gaze had slipped to a spot behind him. That spot was where Ryuk was floating, and for this stranger to see him… it should have been impossible.

And yet, the shinigami gave a laugh as he turned towards her, as if he knew what was happening. “Interesting to see that one here. She hasn’t been in this hemisphere for years.”

Light’s thoughts turned slightly panicked when the girl walked across the street. She was slouching even as she walked, which made her look even smaller than she probably was, with black hair tumbling down her back. She wore the same uniform all junior high girls wore, but he could tell she wasn’t enrolled. She was foreign.

“Um, excuse me, but…”

“I know,” the girl said, in perfect Japanese. She was right in front of him now. “I’m sorry for staring, it’s just… you have an interesting friend.”

_ She uses  _ uchi.  _ Is she from Kansai?  _ Light frowned. “No, don’t worry. Who do you mean?" Best to try and play dumb for now, or his  _ Kira _ secret might be outed just like that. She seemed smart.

"Hm?" She tilted her head quizzically, like she was confused from his lie. "… I guess you aren't that boy. I saw someone earlier, who looked like you, and with him, there was this other one who looked out of place. You're just… a coincidence, then." Her eyes slid to one side and she bit her finger. She must have done that a lot, because all her nails were short.

Light shook his head. "Not to be rude, but who exactly are you? I can tell you aren’t Japanese.”

“I grew up overseas. Then I was sent me here to do something, so I taught myself some of the language. Call me Amy.”

Amy. Definitely from an English country, then. “I’m Light Yagami. It’s a pleasure to meet you.” They shook hands somewhat reluctantly - did Amy not like being touched? “This is a weird place for someone like you to be wandering around.”

“Is it really?” It was formed like a question, but it was just something for her to say. Amy glanced around the area. “Maybe I’m being too literal in looking for a place to stay.”

Was that a joke? Light couldn’t tell. “There are hotels.”

She shrugged almost half-heartedly. “I don’t have much money. Not enough to last.”

“Do you have friends here? Or family?”

“No.”

He frowned and narrowed his eyes. Ryuk was laughing again, behind him. He knew something, Light was sure, which meant that this girl who looked about his sister’s age was important. She could see a shinigami whose notebook she’d probably never touched and smart enough to know not to talk about it, and he had a sneaking suspicion that she was sent to Japan for Kira. Why a kid, he had no idea.  _ Keep your enemies close. Is that a good idea for a situation like this? Dad is working on the case so it might be dangerous… but I need to keep tabs on this girl. I just need a casual way of bringing this up… _

“I have a little sister your age. She could probably help you more than I, if you want to talk to her instead.”

Amy tilted her head once more, carefully regarding him. “… sure. I didn’t have plans and it would be nice to get to know some locals.” She took time to answer, but to Light, it seemed like she’d already decided long ago.

The conversation died as the boy led her to his home, though she didn’t complain once. Maybe her natural state of being was silence? It fit someone who looked so dark and brooding.

Sayu took a liking to Amy instantly and it seemed reciprocated, so Light relaxed just a little and left them to talk before going up to his bedroom and locking the door. He turned to glare at an upside-down Ryuk. “Who  _ is  _ that?”

“Weren’t you listening to her, Light? She’s some kid here on a job.” He was grinning wider than usual, which Light found suspicious.

“She could see you. She looked right at you when she first saw me.” The boy sat at his desk and twirled a pen in his hand. “You’ve seen her before.”

“So? Shinigami can pick favorites among humans.”

Light sighed. “That’s not what I mean. Ryuk, she  _ saw  _ you, and there’s no way she’s touched the notebook. I’ve had it this whole time, and if she’d touched it before then she’d be the owner, which she isn’t.”

“You sound almost scared. What if she just found a scrap of it somewhere?” The shinigami was taunting him.

“It isn’t just that. If she was a normal, innocent person who’d found a page by coincidence, she should’ve screamed at you or something. She didn’t even look surprised. You know what’s going on.”

Ryuk waved his claws in front of his face. “Hey, even if I do, why should I tell you anything?”

“Because if you don’t, she might expose me and your fun might end right here and now.”

“Oh… fine. Let’s see…” Ryuk turned right-side-up and settled on Light’s bed, humming thoughtfully. “Would you be surprised to learn that shinigami aren’t the only immortals out there?”

Light frowned, then shook his head. “Not particularly.”

“Good. One of them happens to be close to the Shinigami King, like, they work really close together, and this kid is that guy’s daughter.”

Light tried to wrap his head around that idea. These other gods must be more human-looking than shinigami. “Is she immortal?”

“Ha, not even close. Her mother was just some regular human woman. But she’s got powers, and since her dad works with death…”

“She can see shinigami.”

“Right on. There aren’t many kids like her out there because of a pact during your World War II, which is part of why I remember her.”

Light cursed and turned to his desk. Other gods, having children with mortals. Children who could freely see shinigami. Children who were sent to suspicious places with mysterious things to do. “If she just dies…” 

“Now, that’d be a cop-out, Light. You’re smarter than that. Besides, I can’t give you her name or kill her directly. I’d get in a lot of trouble!” Ryuk sounded panicked. 

“What else do you know about her?” 

There was silence for a brief moment. 

“… She’d rather tell you herself than have you hear about it from me. She’s a stubborn one.” 

Light sighed. “Fine, then. I’ll deal with her on my own. You won’t tell her anything?” 

He really didn’t need to ask. A knock came at the door. 

“Light, honey? It’s time for dinner, but I know you’re studying hard, so do you want me to bring some up to you?” It was his mother. 

“Yeah, that’s fine… hey, is that Amy girl still here?” 

“Why, yes! She and Sayu are getting along very well. She’s asked to stay over for a few weeks.” 

Light smirked. “Oh? I was worried she wouldn’t find anywhere. She told me she was having issues with funds and that was why she wasn’t going for a hotel.” 

“It’s a good thing she bumped into you, then. Well, anyway, keep at it. I’ll have your food up in a little bit.” Her footsteps retreated. 

Ryuk chuckled. “Looks like you’ll be able to keep a close eye on our new housemate.” 

“That’s right,” said Light. “Now it’s a waiting game - to see which of us finds the other’s secrets first.” 

He brought the Death Note out of its hidden drawer and got to work.


	2. Tagging Along

There was an uncomfortable silence at the dinner table. It had been just under a week since the strange girl, Amy, had arrived to the Yagami household out of nowhere. She seemed to have made herself right at home in Sayu’s bedroom, and more or less spent her time playing games on a laptop she’d brought along with her.

_ Or,  _ amended Chief Yagami of the NPA,  _ she’s doing research on something.  _ Even though he wasn’t at home often, he had gotten to talk with her once or twice and found a secretive nature. She deflected questions or ignored them altogether. Sometimes she would stare blankly and then shrug.  _ There shouldn’t be a need to worry. She’s a teenager, after all. But, still, it’s odd that she’s become so antisocial when she and Sayu seemed so close to begin with… _

“Yagami-san?” Amy was looking at him expectantly, twirling one of her chopsticks absentmindedly. “I have a request. It’s very serious.”

“Amy-chan, but last time you said that, you dragMPH.” Sayu now had three dumplings stuffed into her mouth. How had it happened so fast? Soichiro blinked at the other girl.

“As I said, this is serious. Sweets are serious business, too, but not like this.”

The man nodded encouragingly. “What is it?”

“Ah… I want to come to the station with you tomorrow.” She looked down at her lap. She was picking at the chopstick now.

Across the table, Light frowned. “I’m not sure that Dad’s work is something you’d be interested in. Don’t you like cheesy movies that have happy endings?”

Amy shrugged. “I actually prefer horror and mystery, but that’s irrelevant. See, since I came here, I’ve been doing a lot of research on things that surround my goal, and I believe that the case the NPA is working on right now would be of help. I, um… I’m not sure if I should explain, though. It’s supposed to be a secret to the general public.”

Soichiro frowned and thought it over. If she knew she was talking about the Kira case, there might be a leak. Either that, or this girl was simply smart enough to have deduced it on her own. Something told him it was the latter. In that case, she might be of some help, and if not, at least her curiosity would be sated by a visit to the station. On the other hand, she could end up being a security risk - the police’s involvement was, in fact, meant to be secret. But then he realized that eventually he would have to explain what he was doing to his family, and besides, there had been a television broadcast the previous day that explicitly announced opposition to Kira, and Soichiro nodded. “It’s all right. Considering yesterday’s broadcast, it’s probably obvious that the NPA is working to catch this Kira.”

“And L is helping.” Another silence fell, and the Yagami family looked at Amy. “..? What? Oh… yeah, I do know about L. Sort of. He’s a very good detective and usually, he only takes on cases that present a challenge to him… I knew he’d probably want to be involved with this one, which is part of why I agreed to come to Japan.”

Light leaned forward. “So your job here… it’s to catch Kira? And if you only wanted to do it because of L… “

“It’s a little more complicated than that. I was sent here to make all these killings stop, not necessarily to catch him. Personally, Kira’s work has made me suffer, but if I hadn’t been approached by the person who sent me here, I’d probably have stayed overseas. L… L is someone I’d like to say I know on a personal level. I want to help him however I can, and even if you believe I won’t be able to, Light-san, there are definitely things I know of that you don’t. Now, Yagami-san, I know this is an odd request, but could you please explain to me if there are any new, big developments in the case? I have a theory, but your answer might contradict it and I don’t want to bring in false information.”

_ Come to think of it, her speech patterns are similar to L’s… I wonder how close they are?  _ Soichiro nodded again and closed his eyes. “So far, all of the deaths have been from heart attacks, which is how we were able to track these murders. The only reason we could label them as such was that the victims were always criminals and usually had no health issues that should result in heart attacks. As you probably saw yesterday, this L has been able to narrow down Kira’s whereabouts to this area of Japan, and today he proposed that based on when these deaths occur, Kira is likely to be a student.”

Amy nodded a few times and then, oddly, she smiled. “That makes a lot of sense. I guess… hm, thank you.” She had cut herself off, as if she had something else to say, but then smiled and went on. “Knowing all that, I’d still like to come with you tomorrow. Would that be okay?”

“I don’t see any problem with it, but I don’t think it’s a good idea for you to come into the investigation room with me. The other officers might think it strange and get suspicious. You don’t exactly look like a hardened detective or even a particularly trustworthy person, at first glance.”

“Okay,” said the girl, and the conversation turned to more pleasant topics, like what had happened at school and plans for the next weekend. Soichiro noticed that his son seemed troubled by something every so often, but he rationalized that it was probably nothing more than the stress of his schoolwork.

The next morning, Amy was waiting patiently by the front door with a rice cake in her hand and a messenger bag over her shoulder. “I didn’t want to bother your wife for breakfast, so I just took this.”

The chief assured her that it was completely fine and they left the house, making pleasant small talk until they reached his office. Again, he reminded Amy that she should stay out of the investigation room and she promised that she would not follow him through the door. It was an odd way to phrase it, but there was no other way in, so it wouldn’t matter.

The force was already hard at work; Soichiro had slept in that morning under Matsuda’s suggestion. Speaking of, he saw Matsuda stand up to bring him a cup of coffee as he walked to his desk, and smiled gently. “Thank you, Matsuda. How are things going?”

“W-well, so far we haven’t had any luck, and L has mostly kept silent, but I think we’re about to find something big!” Despite everything so far, Matsuda was an excitable, optimistic young man. The chief found it almost inspiring.

“That doesn’t surprise me. If Kira is really a student then there wouldn’t have been much time to kill anyone… I have something to speak with L about.” He looked up toward the corner where the enigmatic Watari was sitting with L’s laptop open. The man nodded, so Soichiro stood and moved over.

From the computer came the edited voice the police force was just beginning to get used to. “What is it, Yagami-san?”

“It’s… a little hard to explain. There’s a girl who wants to speak to you. She’s been staying with my family for a few days and apparently doing her own research on Kira, and she says she has a theory. She wants to help.”

“A girl..? That’s quite odd. Where did she come from?”

“My son ran into her on his way home from school one day and invited her over. Apparently she needed a place to stay while she was in Japan, and since my wife is who she is, we didn’t have a problem about it. Last night she brought up the idea of coming here, she says she knows you.”

There was a strangely long pause before L spoke again. “How old is she?”

Soichiro frowned. “About my daughter Sayu’s age. Fourteen. There’s… something about her that does remind me of you, now that I think about it. From what I can gather she’s a very smart girl as well.”

“I know who it is. I thought she might want to get involved if she knew that I would, but to do something so drastic, to come so far… where is she now?”

“Well,” came a voice from behind. “Now I’m here. It’s been a long time, L. Watari.” Soichiro turned to find Amy standing a few meters away, a bright smile on her face. “Let’s get to work, shall we?”

**Notes for the Chapter:**

> how do you refer to dad yagami in third person???? oh well.

**Author's Note:**

> I'm trying to write this kind of like a light novel
> 
> short paragraphs
> 
> is it working


End file.
